The inventor of the present invention conducted research and discovered that fats within a living body were decomposed (lipolysis) by irradiating the living body with ultrasonic waves having a specific frequency. A patent application regarding an ultrasonic wave irradiation apparatus was filed and published as PCT Publication Number WO 99/39677 on Aug. 12, 1999.
In the practice of the previous invention, it was required to irradiate the living body with ultrasonic waves. The living body has wide three-dimensionally curved surfaces composed of complicated uneven surfaces such as, e.g., the abdominal region, the thighs, the buttocks or the chin. Therefore, it is difficult to evenly irradiate the surface of a living body with ultrasonic waves.
To solve such a problem, in the published international patent application, there was disclosed:
(1) an apparatus, having an ultrasonic transducer arranged on a side wall of a bath tub, for irradiating a living body via hot water in the bath tub with ultrasonic waves generated by the ultrasonic transducer;
(2) an apparatus, having an ultrasonic transducer arranged on the bottom of a water chamber having an upper side thereof left open, for irradiating, with ultrasonic waves, a living body contacting the water on the upper opening area via the water in the water chamber; and
(3) an apparatus, having an ultrasonic transducer arranged within a shower head, for irradiating, with ultrasonic waves, a living body via water or hot water flowing out from the shower head.
It has been known to irradiate with ultrasonic waves for, e.g., enhancing beauty, acceleration of blood circulation and for curing stiffness in the shoulder or lumbago, and some conventional ultrasonic irradiation apparatuses have been known for these purposes. The conventional ultrasonic irradiation apparatus has a single ultrasonic transducer having a diameter of about 20 to 50 mm, and irradiation, with ultrasonic waves, over a desired wide area of a living body is performed by scanning the living body surface with an acoustic output part of the apparatus.
In the conventional ultrasonic irradiation apparatus, ultrasonically irradiating the living body having three-dimensionally curved surfaces is easily conducted without large size equipment such as a bath tub, a water chamber or a shower system, because scanning can cover the living body surface to some extent. But, when the scanning area becomes wider, in the conventional system it requires a long time to scan wider areas because of the time required to manually scan the single ultrasonic transducer to accumulate the necessary irradiation dose (intensity of irradiation×the accumulated time of irradiation) per unit surface area. Hence, the work load for an operator, such as a doctor, becomes heavier.
In the published international patent application, an apparatus has been disclosed, having a single ultrasonic transducer and an acoustic lens arranged in front of the ultrasonic transducer, for irradiating a living body with ultrasonic waves through a bag containing an ultrasonic conducting medium such as, e.g., water or jelly. In the system of the published patent application, it is possible not only to make close contact with a living body via the water bag, but also to expand the area of irradiation greater than using a sole ultrasonic transducer, due to a function of the acoustic lens, and thereby one is able to effectively scan the living body.
However, in the case where the area to be scanned is wider, the system disclosed in the published international patent application has the same problems as the conventional ultrasonic irradiation apparatus. In other words, it takes a long time to scan wider areas and the load imposed on the operator becomes heavier.
Further, in the apparatus for irradiating ultrasonic waves via a bag containing an ultrasonic conducting medium, the distance between the acoustic lens and a window portion of the bag, which outputs ultrasonic waves and which is in contact with the living body, must become longer to make the irradiation area wider, and thus the amount of water is increased. As the result, the pressure of the water weight is transferred to the living body, and it is difficult to make adjustments so as to partially support and lessen the pressure due to such weight. Further, in the apparatus for irradiating with ultrasonic waves via the bag containing the ultrasonic conducting medium, the position of the living body to be irradiated with ultrasonic waves is limited because, if the irradiation direction to the living body is not vertical, the output window of the bag is greatly deformed by gravity and thereby it is difficult to scan smoothly.